34: SUxMMAllY OF CURRENT RESEARCHES RELATING TO 



seen in the apodous genera Herpele and Ichthyophis in their primitive 

 disposition, scattered on the surface of the cutaneous rings which corre- 

 spond to myomeres. While the mucus glands retain their isolated 

 scattered disposition the granular glands tend to be localized on the 

 dorsal surface. This localization begins in the Apoda and is correlated 

 with the disappearance of scales. One mode of protection replaces 

 another. The secondary changes in the glands — reduction in number, 

 compensatory increase in volume, groupings — are too variable from one 

 genus to another to be of taxonomic value. It is found that the poisonous 

 function of the cutaneous glands is only defensive in a secondary and 

 accessory way. It is inconstant, unequal, and ineffective in most cases, 

 and seems best expressed in forms which need it least. These glands 

 have individual utility rather than species-preserving value. 



Skin of Lumpsuker.* — Albrecht Hase finds that the epidermis of 

 CydopUrm lumpus consists of three layers : (1) a basal layer (without 

 limiting membrane) ; (2 j a median layer of elongated cells, disposed at 

 right angles to the surface, with numerous intercellular spaces ; (3) a 

 more tile-like covering layer, rich in pigment. In the epidermis there 

 are mucus glands in the outer layer, which open directly to the exterior, 

 and very large serous glands which arise from the basal layer. The 

 serous glands occur especially in the median layer, and open by canals 

 perforating the covering layer. 



The cutis consists of three strata : (1) the outermost is stratified and 

 penetrated by perpendicular strands of fibres ; it includes a pigment 

 layer. (2) The middle layer is like a feltwork, penetrated by blood- 

 vessels, etc. (8) The inner layer is stratified. It is not sharply defined 

 from the middle layer, nor the latter from the outer layer. Under the 

 inner layer there is a deposit of pigment. The pigment-cells of the 

 corium are different from those of the epidermis. 



Between the cutis and the musculature there is a loose, wide-meshed 

 connective-tissue, especially in older animals. Between the basal epi- 

 dermic layer and the uppermost corium-cells there are fine plasmic 

 bridges, which traverse the outermost corium layer at right angles. 



The integumentary ossifications are mesodermic ; they are disposed 

 in rows or scattered ; those in rows develop earlier ; their structure it 

 that of trabecular dentine. The whole armature is nearer that of 

 Selachians than that of Teleosteans. The single ossifications are conical 

 in form, and arise by coalescence, thus differing markedly from ordinary 

 Teleostean scales. 



c. G-eneral. 



Warning Colours in Mammals.f — R. I. Pocock comments on the 

 fearlessness of shrews and the readiness with which they may be tamed, 

 to the squeaks they make as they hunt, and to their unpalatability 

 because of a strong musky scent. He suggests that, being unpalatable, 

 they can afford to be self-advertising animals. 



The large Indian musk-shrew (Grocklura cc&rulea) has an unpleasant 

 musky odour ; it makes a peculiar chattering noise, like the jingling of 



* Jen. Zeitschr. Naturw., xlvii. (1911) pp. 217-342 (8 pis, and 37 figs.>. 

 t Ann. Nat. Hist., viii. (1911) pp. 750-7. 



