i;}.| AI.KXANI)U()MP:NIA agassizi. 



Tlie Itoily is siirrmiiidcil l>y a cuticle O.IOS iiiiii. in thickness, and as in the 

 prccpiliufi; species, this is iarjiely occupied by pai)iliae (Plate 33, tig. 5) and spicules 

 of two varieties (Plate 37, (iji. '•>). Of the latter those of one type project from 

 the hypoderniis, with which tliey i-emain connected, almost at right angles and 

 l)r()tru<le freely from the surface of the body. The others, needle-like, relatively 

 small, and slightly curved, form from five to seven irregular layers almost at 

 right angles to th(> first named spines. 



The papillae are fully as numerous as in the succeeding species and the 

 constituent cells are approximatt'ly half as abundant; but the differentiation 

 into stalk ;uul ex])antled part is mA so sharply defined (Plate 33, fig. 5). In many 

 cases the base of the stalk is of great width and expands but slightly as the sur- 

 face of the botly is approached, the jKipilla in such circumstance having a club- 

 shaped appearance. Even in the more typical forms the departure from such a 

 state of affairs is not marked. The cells appear to be all of one type in the distal 

 portion, at all events the nuclei are of essentially the same size, though they vary 

 considerably in shape, and ai'e surrounded by masses of yellowish green pigment. 



On the ventral surface, especially in the region of the mouth, gland cells 

 a])pear in the hy])odermis. In their early stages each is pear-shaped, the stalk 

 being inserted among the hypodermal cells, while the ilistal portion contains a 

 lightly staining almost homogeneous secretion. Later this product becomes 

 more abundant, swelling the c(>ll to twice its original size, and a granular mass 

 appears to make its way by a very delicate pore to the exterior, though this has 

 not been demonstrated to mj' entire satisfaction. 



The main portion of the anterior pedal gland is located between its outlet 

 into the ventral furrow and the radula and its supports. At this point the cells 

 are contiiuious across the mid line and laterally extend as thin plates compressed 

 between the l)ody wall and the proiligious salivary glands (Plate 20, fig. 4). 

 Posteriorly they separate into two groups which pass without any recognizable 

 line of tlemarcation into the posterior pedal ghuul. The cells composing it are 

 of the usual i)yriform type, densely filled with intensely staining secretory 

 products, and are arranged into irregular groups or lobules. In the customary 

 fashion the ductules from each cell open by an intercellular canal into the 

 anterior end of the pedal furrow. 



.\t the point where the anterior pedal gland opens to the exterior the ventral 

 groove becomes a deep excavation (Plate 7, fig. 3) the area of whose walls is 

 incrcas(>d by the presence of extensive dorso-lateral outpouchings and numerous 

 folds corn-sing from the roof half way down the sides. On the posterior face 



