368 ON THE ANATOIY OF A SUPPOSED NEW SPECIES 



Gland cells of two kinds are found, mucous and granular. The former stain brown 

 in Heidenhain's iron haematoxylin and eosiu, and are fairly numerous all over the 

 coenosarc, yet gradually decreasing in number from the bases of the tentacles down- 

 wards. The granular gland cells correspond to the "kornige Drlisenzellen," described 

 by the Hertwigs in Actiniae (1-i). Their gi-anules are very small, and stain black in 

 iron haematoxylin and eosin (Fig. 4). In shape some are narrow and very elongate, 

 while others are almost round or sack-like. In one young polyp (about 4 mm. across 

 the calice) they are very numerous for about 3 mm. below the tentacles, but over 

 the coenosarc between the free portions of the polyps very scarce. In older polyps 

 they are commonly found only at the bases of the tentacles. 



A few oval nuclei occur immediately above the structureless membrane, but there is 

 no well-marked punctate nervous layer except near the bases of the tentacles. Muscular 

 jDrocesses of the cells and distinct muscular fibres are completely absent. The surface 

 of the layer is sometimes covered with mucus, but generally it is sharply defined, and 

 there is no appearance of the ciliation described by the Hertwigs in the Actiniae. 



The ectoderm of the mouth-disc is very similar to the external ectoderm, but rather 

 thicker — about 'O-i mm. — and with a distinct finely punctate layer of nerve fibrils, 

 immediately over the structureless membrane. Some of the cells too have distinct basal 

 muscular processes. Mucous gland cells are numerous, especially near the mouth of the 

 stomodoeum, but gi-anular gland cells are absent. The nematocysts are more numerous 

 than in the external ectoderm and of the same two kinds, the tentacular towards the 

 exterior and the mesenterial around the stomodoeal opening. 



The ectoderm of the tentacles takes the form of batteries of nematocysts (Fig. 6). 

 Each battery is packed in the centre with nematocysts, close to the basal ends of which 

 are a number of rod-shaped, or oval nuclei. Below these and towards the sides of 

 the tentacles the nuclei are round or very slightly oval. All stain homogeneously with 

 iron haematoxylin, the oval, granular nuclei of the external ectoderm being very rare. 

 Under the centre of the battery on the structureless membrane is a thick, finely granular 

 mass with a few supporting fibrils, a great concentration of the nervous layer {n. I. Fig. 6). 

 A few mucous cells occur towards the sides of the batteries, but granular gland cells are 

 absent. The muscular processes of the cells form a well-marked, thin, deeply staining 

 layer on the structureless membrane. They appear to run mainly in a longitudinal 

 direction in respect to the expanded tentacles, and arise principally from the cells around 

 the central mass of nematocysts. In the contracted condition the central part of the 

 battery is sometimes slightly depressed, but generally the nematocyst mass is much 

 pushed out owing to the contractions of these muscles. 



Tentacular nematocysts (Figs. 7 — 10). The tentacular nematocysts, when ripe, 

 with the thread well formed (Fig. 7) are very uniform iu size, about '027 mm. in 

 length by -003 mm. in diameter. The thread is spirally coiled round a central homo- 

 geneous mass of pi-otoplasm, and causes the external membrane of the nematocyst 

 to project over it. The number of coils varies from 20 to 30, but commonly there 

 are about 2-i. In most nematocysts the terminations of the thread cannot be distin- 

 guished, but in some the thread may be seen to end at the base of the capsule in 

 a very finely granular mass of protoplasm, while at the opposite end it runs inwards 



