PROGRESS OF MICROSCOPICAL SCIENCE. 91 



membrane between the annulus tympanicns and the handle of the 

 malleus remains free from capillaries in its normal condition. In the 

 guinea-pig these vascular loops do not exist, but the vessels are ar- 

 ranged in the form of a net with coarse meshes of a quadrangular or 

 pentagonal form. In this animal, moreover, the radiate are strongly- 

 developed in comparison with the circular fibres of the membrana 

 tympani. The arrangement of the nerve in these animals is described 

 as " fork-shaped," the prongs embracing the loops, while the handle 

 unites with a similar projection from the opjiosite series of loops. In 

 the human tympanic membrane the arrangement of the blood-vessels 

 resembles that of the guinea-pig in the absence of looj)s. The vessels 

 themselves, however, are coarser, and the meshes finer than in that 

 animal. The radiate and circular fibres are, moreover, equal in 

 amount. The conclusions from these observations are the following : 

 1. There is a distribution of vessels in the membrana tympani of man 

 peculiar to him. 2. There is a distribution of vessels in the tympanic 

 membrane of the dog, cat, goat, and rabbit, constant in as well as 

 peculiar to them. 3. The arrangement of these vessels in the guinea- 

 pig is peculiar to it. The author then gives instructions for the 

 preparation of the membrane. 



An un-Microscoptc Specimen of an almost Microscopic Group. — A 

 paper has been read before the Eoyal Society,* which was sent by 

 Herr E. Von Willemoes-Suhm, Naturalist to the ' Challenger ' Ex- 

 ploring Expedition. It is upon a new genus of Amphipod crustaceans 

 founded on the capture of a large new Aniphipod, perfectly transparent, 

 and with enormous faceted eyes. The author shows that among the 

 Amj)hipods known to us, Phroniyna is its nearest relation. But there 

 are so many points in which this genus differs from Phronima, that it 

 cannot form a member of the family Phronimidte ; and he therefore 

 proposes to establish for it a new family, Thaumoi^idfe, belonging to 

 the tribe of Hyperina. The form of the head is totally different from 

 that of Phronima ; the antennfe are not situated near the mouth, but 

 at its front, and the enormous faceted eyes occupy its upper surface. 

 TJie first two pairs of thoracic appendages are not, as in Phronima, 

 ambulatory legs, but maxillipeds, so that only five pairs of legs are 

 ambulatory in Tliaumops. The thorax is composed of six segments — 

 the first of which has, on its under side, the vulva .and one pair of 

 maxillipeds ; and the second, representing two segments, bears two 

 pairs of apj)endages, the larger maxillipcd and the first pair of ambu- 

 latory legs. The abdomen consists of five segments, with three pairs 

 of pedes spurii, the caudal appendages being attached to the fourth 

 and fifth segments. The animal being beautifully transparent, the 

 nervous system could be carefully worked out without dissecting it ; 

 the position of the nerves going out from the cephalic ganglion, as 

 well as that of the five pairs of thoracic and the three pairs of abdo- 

 minal ganglia, could be ascertained. The eyes, having at their borders 

 very peculiar appendages, were examined, and a description is given 

 in the jiapcr here abstracted, of the structure of the large crystalline 



* ' Proceedings of E. S.,' April. 



