^Ir. F. P. Pascoc on some new Anthribida. 35 



Tlic nearest analogy I am aware of for wliat occurs in Pyro- 

 soma is the proces^s ot" devcloj)inent of the embryo observed by 

 Kolliker iu Ascai-is deritata and in Cucullanus eleguns, where the 

 yelk is a nearly clear lluid, which undergoes no segmentation, 

 but merely serves to suspend the embiyo-cells. These embryo- 

 cells are, however, according to Kolliker, new products arising 

 totally independently of the germinal vesicle ; so that, if this be 

 the case, there is a fundamental difference between the two pro- 

 cesses — quite apart from the fact that, in the worms, there is a 

 vitelline membrane, and that the representative of the ovisac 

 plays no such part as in Pyrosoma. Indeed, in this respect the 

 development of Pyrosoma appears to be unique, as om- present 

 knowledge stands ; though I strongly suspect that the develop- 

 ment of SaJpu will some day be found to be very similar. No 

 one of the many observers of the Salpce (Krohn, Vogt, myself, 

 Leuckart) have seen yelk-division in these animals; and the 

 passage of the embryo into the atrium appears to be effected in 

 them in essentially the same manner as in Pyrosoma. 



On the other hand, although there is not an exact identity, it 

 must be admitted that there is a very close analogy between the 

 changes undergone by the ovisac of Pyrosoma and that through 

 which the ovum of a bird passes, if we consider the vitelline 

 membrane (i. e. what is ordinarily regarded as such) of the bird's 

 egg to represent the tunica propria of the ovisac of Pyrosoma. 



VI. — On some new Anthribida. 

 By FrxVNCis p. Pascoe, F.L.S. &c. 



[With two Plates.] 



[Concluded from vol. iv. p. 4.39. J 



Xenocerus cquestris. 



X. nigcr ; capite prothoraceque albo-liueatis ; elytris sutura (apice 

 excepto), fascia postica, vittaque basali albo-toraentosis. 



Hah. Aru. 



Elongate, tomentose, dull black ; a white stripe, commencing 

 at the ajjcx of the rostrum on each side, divides beneath the eye, 

 one branch, proceeding over its ui)pcr margin, is continued along 

 the lateral border of the prothorax to the elytron, where, gradu- 

 ally tapering to a point, it terminates at rather more than half 

 its length, the inferior branch, ])assing beneath the eye (which 

 has thu.s a nearly complete border of white encircling it), joins 

 the great mass of pure tlake-white, whicli occupies the whole of 

 the under surface except the pro- and mesosterna ; another 

 stripe, commencing between the eyes, passes along the centre of 

 the prothorax, the scutellum, and suture, to near the declivity at 



3* 



