ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 343 



Lateral Sense-organs of the Head in Macruridse.* — Albert Pfiiller 

 has made a study of these structures, which are usually well-developed 

 in deep-sea fishes. Especially is this the case with the supra-orbital, 

 the infra-orbital, and the operculo-mandibular canals. In all the ten 

 forms examined there are thirty-three sensory prominences, which consist 

 of pear-shaped sensory cells with large nuclei and sensory " hairs " 

 which penetrate the membrana limitans. Between these sensory cells 

 are cylindrical supporting cells. The innervation of the sensory structure 

 is very carefully described. 



The lateral sense-organs of the Macruridae are not luminous organs 

 nor electric organs. They are exquisite sensory organs, which detect 

 slight changes in pressure. The membranes within the sensory canals 

 probably increase the sensitiveness. A new organ, the occipital organ, 

 occurs in all Macruridaa just in front of the first dorsal fin. Its function 

 is obscure. In Macrurus cavernosas there is a peculiar sucker-like 

 structure. 



Penis of Duck.t — Walther Liebe has made a detailed study of 

 the penis of the domestic duck. It is a spirally twisted unpaired 

 structure. It consists of a paired lymphatic space with vascular bodies 

 at its base, and of an unpaired free portion with a glandular sac in its 

 interior. The basal portion is supported by a fibrous body and with 

 this is associated an elastic body which extends in the wall of the 

 glandular sac to the tip of the penis. The erection is due to lymph 

 secreted in the cavities of the vascular bodies. The sperm passes from 

 the urodaeum into the external seminal groove of the penis — a groove 

 which becomes a tube during erection. The anterior pair of penis 

 muscles is connected with the pelvis, the posterior pair with the skin. 

 The surface of the penis is without glands or touch-spots. 



c General. 



Lateral Muscle in Teleostei.J — E. W. Shann has studied this in a 

 variety of types. The body-wall is composed on either side of a series 

 of transverse muscles (myomeres) divided from one another by fascia? of 

 connective-tissue (myocommata). For practical purposes these may be 

 regarded collectively as forming a single lateral muscle, composed of a 

 single layer, varying considerably in thickness. 



In its primary condition, such as obtains in the caudal region, it is 

 divided into two symmetrical longitudinal moieties, which are separated 

 by a horizontal septum passing from beneath the lateral line to the 

 vertebral column. For descriptive purposes, the dorsal moiety may be 

 divided into a (dorsal) mesio-dorsal portion and a (ventral) latero-dorsal 

 portion. In the mesio-dorsal portion the fibres run from above anteriorly 

 to below posteriorly ; in the latero-dorsal portion they take the opposite 

 inclination. The ventral moiety is likewise divided into a (dorsal) 

 latere- ventral portion and a (ventral) mesio-lateral portion. The fibres 



* Jen. Zeitschr. Naturw., lii. (1914) pp. 1-134 (2 pis. and 38 figs.). 

 t Jen. Zeitschr. Naturw., li. (1914) pp. 626-96 (2 pis. and 19 figs.). 

 t Proc. Zool. Soc, 1914, pp. 312-37 (3 figs.). 



