PLEUKECHINUS BOTHRYOIDES. 465 



Pleurechinus bothryoides 



! Pleurechinus bothryoides Agass., 1841, Monog. Seut. 



The genus Pleurechinus corresponds to the genus Opechinus of Desor, -who 

 established it to receive several very characteristic fossil species of Temno- 

 pleuridae, which D'Archiac and Haime distributed in Temnechinus and in 

 Temnopleurus. Only a single recent species is known, and only a single de- 

 nuded test, which is now a part of Michelin's collection, in the Museum of 

 the Ecole des Mines. It is unfortunately in such a condition that no specific 

 description of any value can be made, and I can do nothing except to call 

 attention to the species, totally unlike, as far as it goes, any other species 

 of Temnopleuridae known to me. There are four deep disconnected pits of 

 about equal size along the sutures of the plates above the ambitus ; the pits are 

 separated by primary tubercles of uniform size, forming three principal verti- 

 cal rows, with two outer rows of smaller tubercles, separating the pits from 

 the narrow undulating poriferous zone. There are two pits in the ambulacral 

 system, with two principal outer vertical rows of primary tubercles, and two 

 irregular median vertical rows of smaller tubercles. The test of this species 

 is quite high, ovoid, with an outline recalling somewhat Amblypneustes. 

 Abactinal and actinal systems, as well as spines, wanting ; color of test dark 

 violet, with white tubercles. 



In the Jardin des Plantes an old specimen of Temnopleurus toreumaticus 

 is also labelled E. bothryoides by Agassiz, which must not be confounded with 

 the specimen of Michelin's collection. The Pleurechinus bothryoides of 

 Agassiz, mentioned in the Anatomie du Genre Echinus, is evidently, from 

 the short description, something very different.* This species, as well as 

 several specimens of Temnopleurus and Amblypneustes, is marked as 

 coming from the Galapagos ; there is probably a mistake in the locality, most 

 of the specimens having been purchased from dimming, and are undoubtedly 

 from the East India Archipelago or the Philippine Islands, as the same 

 species in the British Museum, collected by Cumming, are labelled in that 

 way. 



* It is probable that the Pleurechinus bothryoides mentioned in the Anatomie du Genre Echinus is 

 the adult Microcyphus zigzag, as there are several large specimens of M, zigzag in Michelin's collection 

 without labels either from Michelin or from Agassiz. 



