138 IWAJI IKE DA. 



occur in Hauiingia arctica/ are found in the genital 

 groove. 



The papillary bodies are scattered almost uniformly over 

 the non-wrinkled surface, but they are more densely crowded 

 at places where the skin is more contracted. When viewed 

 from the surface they appear as small opaque patches of 

 irregular shape and various size, which are separated from 

 each other mostly by numerous light, transverse furrows, 

 varying somewhat in length and in their course (fig. 3), 

 Most of them are nearly flat, but some of larger size 

 (measuring 0*3-0'4 mm. in diameter) are slightly elevated 

 above the skin-surface. Each structure (tig. 4) looks, if 

 seen by transmitted light, like a thick accumulation of very 

 small refringent granules heaped up into several smaller 

 irregular-shaped masses. Some of the granules are seen to 

 be of the same nature as those found dispersed throughout 

 the general surface of the skin. In the wrinkled regions, 

 also, the papillary bodies are constantly present, and are 

 crowded on to the very ridges of the transverse skin-folds. 

 The only difference which exists between them and the dis- 

 persed papillas is that they are a little smaller in size and 

 more irregular in shape. 



The structure of the skin resembles that described by 

 Horst- in Hamingia arctica ( = gracilis), that is, the 

 skin is composed of six distinct layers — the epidermis, the 

 cutis, the outer circular, the middle longitudinal, the inner 

 oblique muscles, and the peritoneal epithelium. But the 

 present species shows some points of peculiarity with regard 

 to the histology of the cutis and the epidermis. The cutis 

 (fig. 5, en.), which is the thickest of all the dermal layers, 

 consists essentially of a gelatinous matrix, which is traversed 

 by very numerous and highly delicate fibrils (fh.) running 



' Danielsen, D. C, and Koren, J., 'The Norwei^ian North Expedition, 

 1876-1878; Gephyrea (Zoology), 1881, Cbvistiania.' 



- Horst, R., " Die Gepliyrea gesannuelt wiihrend der zwei ersten 

 Fahrten des " Willem Bareiit," "' • NiederLnid. Arch, fiir Zool.." suppl., 

 Bd. i2, 1881. 



