INVERTEBEATA, CRYPTOGAMIA, MICROSCOPY, ETC. 83 



1. Systematic. — The author considers that the differences between 

 Typhloscolex, Sagitella* and Acicularia are of merely specific value, 

 and that the two latter genera ought therefore to be merged in the first- 

 named. If the anterior row of setse found in some forms should turn 

 out to be a constant and not merely a larval character, there will be 

 three species of Typhloscolex, namely : — 



(a) T. Miilleri, with anterior row of setae (including Sagitella 

 KowalevsJcii N. Wagner, form b ; larva of Acicularia Virchoioii 

 Greeff ; Sagitella barbata Uljanin). 



(b) T. KotvalevsJcii, without anterior row of setae (Sagitella Kowa- 

 levsJcii N. Wagner, form a ; Acicularia Virchowii Langerhans ; Sagitella 

 KowalevsJcii Uljanin). 



(c) T. prcecox Uljanin. 



If, on the other hand, the setae are proved by further study to be a 

 larval character, all these forms will be included in the one species, 

 T. Miilleri. 



2. Digestive Organs. — The alimentary canal consists not, as usually 

 described, of two, but of three parts : a muscular oesophagus, in con- 

 nection with which is the remarkable glandular proboscis, a glandular 

 stomach, and an intestine. 



The oesophagus is lined with a layer of cells, external to which 

 are the strong, radially disposed muscle-cells, and then much thinner 

 layers of longitudinal and circular fibres. The " retort-shaped 

 organ" or proboscis already referred to, lies, as described by 

 Uljanin, in a dorsal pouch of the gullet, its narrow end projecting 

 into the mouth. It is indistinctly divided into a right and a left half, 

 and in section shows an irregular network of fibres, with interspersed 

 nuclei. 



On each side of this body is a smaller flask-shaped glandular 

 organ, a duct from the pointed end of which comes into close relation 

 with the proboscis. Greefi: thinks, but has not been able to jirove, 

 that the flask-shaped organs are glands, pouring their secretion into 

 the retort-shaped organ, which must thus act as a bladder or receptacle 

 for the secretion. 



In the hitherto undistinguished stomach the epithelial cells are 

 radially elongated to such an extent as to resemble the muscle-cells 

 of tlic gullet. They are seen, however, to be continuous with the 

 epithelium of that part of the canal ; and the muscular layer of the 

 stomach, as well as that of the intestine, is quite insignificant. The 

 epithelial cells of the intestine are greatly vacuolated, so as to resemble 

 the cells of the uotochord.f 



3. Itod-containing Organs. — The author extends his former account J 

 of the cup-like, rod-containing organs (Stabchenbiiudcl) discovered by 

 him in the parapodia. He has observed the development of these 

 organs, each from a single cell of the parapodium, some cells being 

 seen in which the nucleus, or often two nuclei, still remained, and 

 was surrounded by a circle of rods. These latter arc found to be 



* This Journal, ii. 1879) p. 425. 



t Or the endodcrm-ccUs of a Hydroznon. 



X This .Journal, ii. (1870) p. SS:!. 



a 2 



