366 Tetrarhynchus erinaceus 
given a general account of the development of the mature worm from 
the encysted scolex, and a general account of the anatomy of the 
proglottis, which although lacking in detail is very accurate so far as it 
goes. Pintner (1880 and 1893) has described the general anatomy of 
several species of Tetrarhynchus (hut not T. erinaceus)] and Vaullegeard 
(1889) has described, without much detail, the organs of the Cestode 
in question. Vaullegeard’s paper is a general account of the whole 
genus so far as it was known, and it includes a very exhaustive biblio¬ 
graphy of the memoirs written with respect to Tetrarhynchids. I refer 
the reader to this paper rather than attempt to give a detailed list of 
the literature relative to T. erinaceus. Linton (1891) has also described 
an apparently new species under the name of Rhynchobothrium im- 
parisj)ine,\)\\t Vaullegeard refers this species to T. erinaceus. I am not 
sure that the two species are identical but in the absence of a more 
detailed description than that given by Linton it is impossible to be 
sure of this. There are also other references in the literature to the 
occurrence of T. erinaceus, but with the exceptions of van Beneden’s 
first accounts and Vaullegeard’s memoir, neither of which deals in 
detail with the anatomy of the worm, there are no good accounts of the 
species. 
I began in 1907 to work on van Beneden’s species but have always 
found difficulty in obtaining sufficient material. The mature worm 
occurs in the large intestine of various species of Skate and Ray: Raia 
clavata, R. maculata, R. hatis, R. circularis and R. microcellata, all 
obtained from the fishing grounds in the Irish Sea. It is always 
attached to the spiral valve at the anterior end of the large intestine, 
though free proglottides may be found quite near to the anus. The 
gut of these fishes is best examined for tapeworms and flukes by 
dissecting it out, and slitting it up with a pair of scissors so that every 
fold of the spiral valve is cut through. The gut is then placed in 
a photographer’s developing dish containing water in which stands 
a large “ crystallising dish ” filled with water; and then fold after fold 
of the spiral valve is lifted over the edge of the crystallising dish and 
scraped with the back of a scalpel. In this way one can hardly fail to 
see any Trematodes or Cestodes that may be present. Any tapeworms 
found are best preserved as entire objects by killing them in fresh 
water and then fixing in 3 per cent, formalin: this method is not 
good for sections of the worm, but one obtains beautifully relaxed 
specimens with bothridia, etc. fully expanded, and with the tissues very 
transparent so that good whole cleared prepai’ations can be obtained. 
