14 University of California Publications in Zoology. [ VoL - 4 



Boltenia echinata, n. sp. 



PI. 2, figs. 17 to 19. 



Superficial Characters. Body ovate to elongate, surface beset. 

 with simple, slender, sharp, rather remote spines. Siphons dis- 

 tinct or not, at nearly opposite ends of body. Peduncle slender, 

 of nearly uniform diameter throughout, slightly thicker at junc- 

 tion with the body; attached to dorsal side somewhat nearer the 

 branchial orifice, starting off at a sharp angle with the long axis 

 of the body. Color brownish white, body and peduncle nearly 

 the same. Greatest length of body 1.75 cm. to 2 cm., greatest 

 thickness 1 cm. to 1.5 cm. Length of peduncle two to three times 

 that of body, greatest thickness of peduncle not more than 4 mm. 

 Test, very thin but firm and parchment-like, of uniform thick- 

 ness, semi-transparent; entire body spiny, the spines of several 

 lengths, slender, sharp, usually unbranched, but an occasional 

 long one with one or more secondary processes. Each spine situ- 

 ated on a raised, clearly delimited area of test, the larger ones 

 on larger areas, the smaller on smaller areas. No spines on prox- 

 imal half of peduncle. 



Mantle, very thin and closely adherent to the test, muscula- 

 ture consisting of a set of small, moderately numerous, regularly 

 arranged and evenly spaced radial and circular bands, the radials 

 of both orifices distinctly stronger than the circulars; and in 

 addition a felt-work of much finer fibres. 



Branch nil Apparatus. Siphons so short as to be unrecogniz- 

 able in preserved specimens, or but little projecting from the 

 surface of body, both regularly four-lobed. Tentacles about 

 twenty, of unequal sizes, the largest long and copiously branched, 

 the few strong primary branches carrying a great number of 

 secondary branches. Hypopliyseal moutJi simple horse-shoe 

 shaped, about as long as broad. Branchial membrane with 

 twelve folds of very unequal size; internal longitudinal vessels, 

 five or six on each face of the largest folds with one or two be- 

 tween the folds, small and all nearly of same size. Stigmata 

 directed transit rx<-l\i to the longitudinal vessels, in general 

 regularly elongate but in some regions shorter and with 



