12 T. KOMAI : STUDIES ON TWO ABERRANT CTF.NOPHORES 



Hertwig, '8o; "Stadien A & B", Samassa, '92; "Schleimzelle", Schneider, 

 '02) (c. g) vary both in size and appearance to a certain degree. Those 

 which occur predominantly in the dorsal epidermis are of a swollen 

 appearance, being filled up with a homogeneous-looking matter which 

 shows affinity for basis dyes such as haematoxylin and safranin. 

 Superficially and wedged in between the ends of gland cells, there is a 

 scattered occurrence of a peculiar kind of clear cells {c. g) which present 

 a shrunken appearance and take up dyes more strongly than the 

 ordinary clear cells. These evidently represent senescent stages of the 

 clear gland cells after the discharge of their contents. 



The interstitial cells {i. c) form an irregular layer in the basal 

 parts of the epidermis. The nuclei are of a somewhat oval shape, 

 measuring 3 /" by 2 /m, and are provided each with a nuceolus situated 

 in the centre. In the peripheral half of the thickness of the epidermis, 

 one meets but seldom with nuclei referable to the interstitial cells. 



The dorsal epidermis is structured similarly in all parts of the 

 body, except in the part forming the dorsal tentacles as well as the part 

 about the aboral sense-organ to be dealt with later. 



On the dorsal tentacles, the epidermis is made up principally of 

 the interstitial cells, the glandular elements being found only in a 

 scattered distribution. At the tip of the dorsal tentacles, the epidermis, 

 as also the entoderm directly underlying it, is reduced to a very thin 

 layer which takes up stains but faintly and shows at intervals some 

 flattened nuclei. 



In the surface view of fresh specimens (PI. 4, fig. 4), the dorsal 

 epidermis presents an appearance not unlike that of vegetable parenchyme, 

 all the constituent cells being of a distinctly polygonal shape. The 

 distinction between the two kinds of gland cells is quite manifest. 

 Those of the one kind are filled with yellowish refringent granules 

 {g. g), while those of the other kind are of a clear appearance. Closer 

 examination of the latter kind shows that, this is again divisible into 

 two sorts, namely, the larger with a swollen and perfectly clear appear- 

 ance {c. g) and the smaller of a somewhat irregular shape and translu- 

 cent api^earance {c. g). These two sorts correspond without doubt 

 respectively to those two kinds of clear cells of the dorsal epidermis 

 described above, one to the ordinary kind and the other to that of the 

 .senescent stage. 



As regards the thickness of the epidermis, some topographical 

 differences are to be found. In the central parts of the dorsal 



