ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 739 



He points out that tlie parenchyma of Gordius lias at no time, as 

 has been supposed, an enteric function, that the genital organs are 

 very simple, there being two testicles or two ovaries with their ducts, 

 a cloaca, and an " ano-genital " orifice at the posterior end of the 

 body. The atrophy of the digestive apparatus is explained by the 

 simple fact that the animal no longer requires nutriment, while 

 the greater development of the nervous system at this stage is due to 

 its free habit of life. 



Monograph of the Anguillulidse.* — Dr. L. Oerley has a resume in 

 German, in which he notices the chief results of his studies. He 

 finds that the species which have the corium feebly developed, but a 

 strong cuticle, are the best able to resist external agencies. The 

 cuticle is structureless, while the corium is fibrous, and not, as 

 Biitsehli thought, multilaminate. On account of the great difficulties 

 associated with the study of the muscular system, the author thinks 

 that it is better not to use its characters in systematic work ; this, of 

 course, is in opposition to the well-known views of Biitsehli. The 

 efi'erent duct of the excretory organ is strongly chitinized, and the 

 whole of the renal vessel is provided with an extremely fine chitinous 

 layer. The presence of glandular tubes in the region of the mouth 

 of A. aceti is distinctly denied. The author details the following 

 experiment, to show how slight is the need for a special respiratory 

 system. A number of A. aceti were placed in a vessel and covered 

 by a layer of oil an inch thick ; after two months, the greater number 

 of these were still alive. The sensory organs of Jlonhysfera stagnalis 

 are solely represented by pigmeut-spots, there being no lens or any 

 other such structure. The mouth and buccal cavity vary considerably 

 in the diflerent genera ; in an undescribed species of Plectus the 

 author has found another kind of modification of the cesophagus, by 

 means of which the tube is divided into two elongated-oval bulbs. A 

 glandular function is ascribed to the cellular mass which is so fre- 

 quently found around the oesophagus. In Dorylaimus stagnalis tubules 

 were seen passing from the mass into the oesophagus, and the author 

 suggests that the secretion may possibly serve in the renovation of 

 the oral spines. 



In describing the development of Anguillula aceti, the writer 

 observes that the unfertilized egg is always devoid of a membrane, 

 which only appears after fertilization. The bilaminate condition of 

 the embryo is certainly arrived at by a process of delamination. A 

 clear band in the centre of the disk announces the development 

 of the coelom. The month and anus are ectodermal invaginations ; 

 the oesophagus is first indicated by a wavy line, around which the 

 enteric cells become arranged. The whole of the genital tube (at 

 any rate in Diplogaster macrodon n. sp.) is formed from the division 

 of two terminal cells ; in the male the lower terminal cell divides in 

 the direction of its long axis, while in the female terminal cells 

 multiply and form the ovary. 



The author divides the Nematodes into three groups : (a) Parasita 



* Termes, Fuzetek, iv. (ISSO) pp. 1-165 (7 pis.). 



