Ryder.] ^^^ [Oct. 4, 



of metazoaa development, seen in the living Coelenterata, in wlilcli the 

 goblet- cell type of epidermal gland first appears. This persistence is due 

 to the persistence of the physical conditions favoring the survival of such 

 a primitive type of gland, the epithelium of the alimentary canal of even 

 the highest types being constantly bathed with fluids, in much the same 

 .way as the skins of the lowest aquatic vertebrates and the ccelenterates are 

 constantly in contact with the surrounding water. 



2. The marsipobranchs are anomalous. The slime glands or lateral 

 sacks of Mi/xine, with their singular coiled-up bodies, first described by J. 

 Miiller, are not of epidermal origin, but lie in or beneath the corium. 



The representatives of the goblet cells are the refringent clavate glan- 

 dular cells so numerous and embedded at various depths in the epidermis 

 of the adult lamprey, with their narrow bases resting upon the corium. 

 In the young lamprey these cells are superficial and rounded, occupying 

 more nearly the position of goblet cells. The inference, therefore, is that 

 the Kolben and Korner-zellen of the epidermis of marsipobranchs 

 have wandered inwards from the surface into the deeper parts of the epi- 

 dermis, and have been probably derived from what were primarily goblet 

 cells. 



B. — 1. The Batrachia are characterized throughout by the possession of 

 a remarkably developed system of epidermal glands. The function of 

 these organs in batrachians is doubtless manifold, while their structure is 

 extremely simple, being mere flask-shaped organs over most of the integ- 

 ument, and having a very extensive distribution, extending even over the 

 eyelids, tympanic membrane and under surfaces of the manus and pes. 

 The only departures from the simple flask-shaped type of tbe skin glands 

 in this group is on the under surface of the pes and manus and in the 

 parotid region of certain salamanders {Chioglossa, Wiedersheim). In 

 some of these cases there is a slight tendency for these organs to become 

 racemose; but this is rare and exceptional, just as it is lare and excep- 

 tional for the sudoriferous glands of Mammalia to become racemose, 

 those of hippopotamus showing this tendency (Weber). 



The function of the epidermal glands of Batrachia is to pour out a 

 whitish, viscid and very acrid secretion. The inner ends of the secretory 

 cells of the walls of the glandular sacks are sharply defined and are sep- 

 erated by a very distinct outline from the mass of secreted matter con- 

 tained in the follicle. The method of secretion is therefore not akin to 

 that of the cells of a mucus gland; the nuclei of the secreting cells do not, 

 as in the latter, occupy a quite peripheral position. 



The secretion is, however, very mucus-like, as is easily learned upon 

 handling the common frog where the skin is constantly bathed by the se- 

 cretion. It is known to be also very poisonous if injected into the blood 

 of warm-blooded animals, the secretion being also highly poisonous to 

 other species of batrachians if injected into their vessels, death in all 

 cases resulting in a few hours. 



It is also intensely acrid in some if not in all forms ; that secreted by 



