DORYMENIA ACUTA. 97 



the gut and Hr' Ixjdy wall. The colls, where not compressed, are pear shaped 

 with a diameter ranging from .OlSo-.OSol nun. In the early stages of their 

 existence the cytoplasm is vacuolated and not affected with haematoxylin hut 

 with the assumption of glandular activity th(> secretion, in the form of fine 

 darkly staining granules, appears in the peripheral portions of the cell gradually 

 filling the more central portions with the exception of the small, and at this 

 stage, much shrunken nucleus. Delicate ducts, as usual, lead from the cell 

 body to their intercellular opening into the anterior end of the pedal furrow. 



From external view the opening of the anterior pedal gland is not marked 

 by any noteworthy peculiarity, but from sections it may be seen that the pedal 

 groove soon expands inwardly into two extensive lateral diverticula (Plate 15, 

 fig. 1), whose anterior walls, in some specimens, are thrown into low folds and 

 more posteriorly are supplied with very heavy cilia, ranging from one to three 

 times the length of the supporting cell. Along the median dorsal line a large 

 fold exists which more posteriorly is continuous with the foot. Everywhere 

 throughout this fold and over the anterior folds of each crypt the secretion makes 

 its exit in the form of a very finely granular almost homogeneous substance and 

 after treatment with haematoxylin of a slightly pinkish tint. 



The posterior pedal gland is also well developed and consists of a rod of 

 cells on each side of the mid ventral line continuous in front with those of the 

 anterior pedal gland with which they are identical save for their slightly smaller 

 size. Posteriorly thej^ gradually diminish in bulk and number, and in the region 

 of the cloaca finallj' disappear. 



The foot consists of very little more than a V-shaped epithelial fold, the 

 included muscle and connective tissue being very scanty, and entirely devoid 

 of blood sinuses or at all events those of sufficiinit size to include blood corpuscles 

 in preserved material. Throughout its entire extent it is accompanied by two 

 small epithelial ridges which are to ])o considered special modifications of the 

 hypodermis. The inter-cellular openings of the pedal gland occur in the angle 

 formed by these ridges and the foot. 



The atrial opening, holding the usual subtcrminal ])osition, leads into a 

 cavity possessing essentially the same relations as in various species of Neo- 

 menidae. Like Proncomcnia hawaiiensis, for example, there are two conspicu- 

 ous ridges surrounding the cirrose area, and external to the outer buccal ridge 

 a low elevation encircles the cavity save in the mid line jiosterioi-ly. From this 

 elevation numerous delicate fibrils may be traced to a rod-like accunnilation 

 of ganglion cells coextensive with the ridge itself. On the other hand these 



