30 SUMMARY OF CURRENT RESEARCHES RELATING TO 



the endothelial origin of phagocytic mononuclear blood-cells. There is 

 negative evidence also, showing that these cells are not of myeloblastic 

 or lymphoblastic origin, and that few phagocytic cells of any variety are 

 present in normal extravascular tissue. J. A. T, 



Structure of Corpus adiposum buccse. — R. E. Scammon (Anat. 



Record, 1919, 15, 267-87, 9 figs.). This "sucking pad" is a sharply 



•circumscribed mass of fat lobules formed around the radicles of the 



middle part of the venous plexus which connects the orbital veins Avith 



the superficial veins of the face. It appears very early, being mapped 



out in foetuses 4-5 cm. long. It is a definitely encapsulated area in 



foetuses 8-10 cm. long ; fat-cells appear at this stage, or a little later. 



They are arranged in lobules which are first found in the periphery of 



the anterior part of the body. It grows rapidly after the encapsulated 



area has been established ; most of the early growth is due to the 



expansion of the enclosed mesenchymal and pre-adipose tissue and not 



to the growth of fat-cells. The later growth is due to an increase in 



the number of fat-lobules, the formation of new fat-cells, and the growth 



of individual fat-cells. The finer structure of the fully developed corpus 



adiposum does not differ from that of ordinary superficial adipose tissue, 



except that the interlobular septa are somewhat narrower and are 



arranged radially. The body persists in adult life in the large majority 



of cases. Its persistence does not seem to be associated with nutrition. 



There is no evidence for the theory that the body represents the remains 



of the orbital salivary gland. J. A. T. 



Epiphysis of Dogfish. — Nils Holmgren (Arkiv Zool, 1918, 11, 

 No. 23, 1-28, 2 pis.). In Squalus acanthias there are distinct sensory 

 oells projecting into the lumen of the epiphysis. The terminal portion 

 projecting into the lumen varies greatly in appearance and appears to 

 liberate secreted material into the lumen. The sensory cell seems to 

 have in part a secretory activity^ the stages of which are described. In 

 the wall of the whole epiphysis there are numerous ganglion cells, but 

 Holmgren found no neuroglia or ependym. The epiphysial nerve 

 strands are described. Yery remarkable is the secretion-process of the 

 sensory cells which starts from a formed body that appears in all the 

 sensory cells at certain times. There is then a clear differentiation 

 between an inner and outer portion, the latter with a spiral filament. 

 The terminal portion presents marked resemblance to the rods of eyes, 

 and the author works out the probable homology in detail. It would 

 corroborate the theory which ranks the epiphysis with the eyes. 



J. A. T. 



Parietal Organs of Frog.— Nils Holmgren {Arkiv Zool., 1918, 

 11, No. 24, 1-13). An account is given of the terminal vesicle or 

 frontal organ (in the skin) and of the proximal portion, or epiphysis. 

 The latter lies dorsal to the thalamencephalon in the region of the 

 superior commissure between the twohabenular ganglia. In both parts 

 or organs three kinds of cells are to be distinguished — sensory, gang- 

 lionic and epithelial. These are described and figured in detail. In 

 minute structure there is a close resemblance between the frog's 



