134 ALEXANDROMENIA AGASSIZI. 



Tlie body is surrounded by a cuticle 0.108 mm. in thickness, and as in the 

 preceding species, this is largely occupied by papillae (Plate 33, fig. 5) and spicules 

 of two varieties (Plate 37, fig. 9). Of the latter those of one type project from 

 the hypodermis, with which they remain connected, almost at right angles and 

 protrude 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 the first named spines. 



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

 constituent cells are approximately half as abundant; but the differentiation 

 into stalk and expanded part is not 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 body is approached, the papilla 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 are surrounded by masses of yellowish green pigment. 



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

 appear in the hypodermis. In their early stages each is pear-shaped, the stalk 

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

 lightly staining almost homogeneous secretion. Later this product becomes 

 more abundant, swelling the cell 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 my 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 continuous across the mid line and laterally extend as thin plates compressed 

 between the body wall and the prodigious salivary glands (Plate 20, fig. 4). 

 Posteriorly they separate into two groups which pass without any recognizable 

 line of demarcation into the posterior pedal gland. The cells composing it are 

 of the usual pyriform 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. 



At 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 

 increased by the presence of extensive dorso-lateral outpouchings and numerous 

 folds coursing from the roof half way down the sides. On the posterior face 



I 



