ECHINOIDEA 



329 



a monstrosity (cf. Echinocardium fiavescens and Brissopsis 

 lyrifera). A large form from the Mediterranean with un- 

 usually broad petals corresponds to 

 the fossil (post - Pliocene) Spat, di 

 Stefanoi Checchia-Rispoli, and may be 

 distinguished as a separate variety 

 under this name ; it may perhaps 

 also be found in the British seas 

 (cf. Th. Mortensen, Die Echiniden des 

 Mittelmeeres, p. 22, Taf. 2, 1). 



A small bivalve mollusc, Montacuta 

 substriata Montagu, is sometimes found 

 attached to the spines of this Spatan- 

 goid. 



The breeding season is in the 

 summer months. The Zarva (Fig. 191) 

 is characterised by its exceedingly long 

 posterior process. Postero -lateral rods 

 simple with only a few thorns . Hybrids 

 between this and the following species 

 apjoear to be not very rare. 



In British seas this species occurs 

 all round the coasts, in places at least 

 very common, so that great numbers 

 may be taken in a single haul ; also 

 recorded from the Rockall Bank. It 

 is elsewhere distributed from North 

 Cape to the Azores and the Mediterranean, but is not found at 

 Greenland or the Atlantic coasts of N. America. The bathy- 

 metrical distribution is from lowermost tide limit to ca. 900 m. 



Fig. 191. — Larva of Spat- 

 angus purpureus. x 25. 

 (From 

 Fauna.) 



Danniark^ s 



2, Spatangus Rasclii Loven. (Figs. 192, 193.) 



(Syn. Spatangus meridionalis Norman, non Risso.) 



Test high, rising rather abruptly from the anterior end. 

 Mouth rather deeply sunk, labrum prominent (Fig. 192, 1). Area 

 enclosed by the subanal fasciole not twice as broad as long 

 (Fig. 193) ; the fasciole sometimes indistinct, may even totally 

 disappear. Large tubercles (spines) of the upper side not so 

 conspicuous as in purpureus, occurring also in the* ambulacra 

 between the petals and the ambitus. Colour deep violet -purple. 

 Reaches about the same size as purpureus. 



