E. multicostatus is very  characteristic with multiple, very tight, thin and wavy ribs.

They are commonly called wave or brain cacti because of their crinkly appearance. Because the undulating ribs on this small, spherical cactus are so numerous (up to 150) and so closely spaced most of what you see is the wavy brain-like surface of the plant.
 

Description: Stems: Solitary, globose, vivid green with a flat tops  8-15cm wide and up to 7-12 cm tall, typically with 50 to 100 (150) multiple, very tight, thin, wavy ribs
Areoles & spines: There are only 2 or 3 areoles in each rib, witch are covered with white felt in young plants, each has 6 to 9 radial spines, the upper ones are longer whit a central stout and flat erected spine, while the lower ones are shorter and point downwards. The spines are different lengths.
Flowers: The blooms are white with a violet to purple midvien in early spring.  

Cultivation:  Small growing and easy to to care and flower. Because of it’s small size makes a great potted plant specimen, great for beginning collectors. It needs regular cacti soil with good drainage. Propagation: Seeds (usually) or by the shoots of adult plants (if available). Exposure: need some direct sun but is tolerant and prefers light shade during the hot Summer months, allow to dry between watering. Watering should be curtailed during the winter months. Frost Tolerance -5°C if kept dry.

Scientific name:  Echinofossulocactus multicostatus  (Hildmann ex K. Schumann) Britton et Rose 1922

Tribe:  Cacteae -- Subtribe: Echinocactinae

Origin: Mexico (Coahuila, Chihuahua, Durango).

Conservation status: Listed in CITES appendix 2.
 

Synonyms:

• Echinofossulocactus multicostatus (Hildmann ex K. Schumann) Britton et Rose 1922
  = Stenocactus multicostatus (Hildmann ex K. Schumann) A. Berger 1929,
  = Echinocactus multicostatus Hildmann ex K. Schumann 1898
• Echinofossulocactus lloydii Britton et Rose 1922
  = Stenocactus lloydii (Britton et Rose) A. Berger 1929
• Echinofossulocactus zacatecasensis Britton et Rose 1922
  = Stenocactus zacatecasensis (Britton et Rose) A. Berger 1929
• Echinofossulocactus erectocentrus Backeberg 1961 n.v.p Meyrán 1977

E. multicostatus  found in cultivation are quite variable,  and the dissimilarity among seedlings spination and ribs shape may be considerable.

Photo of conspecific taxa, varieties, forms and cultivars of plants belonging to the Echinofossulocactus multicostatus complex (This Taxon has lots of synonyms (like most Echinofossulocactus) whit several controversial varieties and subspecies):

• E. multicastatus
• E. multicostatus forma cristata
• E. erectocentrus (multicostatus)
• E. lloydii (multicostatus)