420 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
relation to tlie attaching disc and to the parenchymatous structure in the 
interior of the head ; both consist of evaginated integumentary layers, 
under which there is a cap-like muscular layer. 
Parasitic Worms of Fresh-water Fish.* — M. F. Zschokke analyses 
a collection of parasitic worms found in 23 species of fish. In the first 
table is given a list of the parasites, with the number of hosts. In the 
second is found a list of the hosts, under each of which is enumerated 
the special parasites and their anatomical position. Table III. shows 
to which class the worms belong. Much of the communication deals 
with the geographical distribution and the derivation of the parasites. 
Incertee Sedis. 
Anatomy of Actinotrocha.! — Mr. A. T. Masterman has a prelimi- 
nary note on the anatomy of Actinotrocha , and its bearing upon the 
suggested Chordate affinities of Phoronis. He states that he has found 
in Actinotrocha an organ which appears to be the homologue of the 
notochord, as well as other characters so much resembling those of the 
Hemichordata that Actinotrocha appears to bear the same relation to 
Balanoglossus and Phoronis respectively, as the tailed ascidian larva does 
to Amphioxus and to the adult ascidian. Comparing Actinotrocha with 
Tornaria in their leading characters, he finds six features common to 
both : — (1) a bilaterally symmetrical, triploblastic, pelagic larva; (2) a 
complete and functional alimentary canal, a ventral mouth, a short 
gullet, and terminal anus ; (3) a large pre-oral lobe covering over the 
mouth ; (4) three ciliated bands ; (5) a thickened apical pla*te on the 
surface of the pre-oral lobe, bearing in most cases a pair of eye-spots ; 
(6) mesoblast consisting mostly of an unpaired coelomic sac in the pre- 
oral lobe, and two pairs of post-oral coelomic sacs. The author believes 
that some extremely important generalisations flow from the above facts, 
but he leaves this for his complete paper, which will, we hope, be shortly 
published. 
Rotatoria. 
Rotifera of County Mayo.t — Mr. J. Hood has a report on the 
species of Rotifera observed by him in the lakes, ponds, marshes, and 
bog pools within a radius of some 16 miles of the town of Westport. 
He regards it merely as an instalment towards a more extensive cata- 
logue, and hopes it may give some idea of the exceeding richness of the 
fauna. Longer residence in the district can hardly fail to result in the 
discovery of many other local species. The want of boats on the many 
small lakes has doubtless prevented the discovery of many forms which 
haunt the deeper waters, and the circumstance that his visits have all 
taken place nearly at the same time of year may have led to the omission 
of many more which become plentiful at other seasons. The author 
points out that very few countries offer such advantages to the student 
of fresh- water life as the West of Ireland. It is, he says, indeed a 
happy hunting-ground with its countless lakes, its deep swamps of 
* Centralbl. f. Bakteriol. u. Parasitenk., xix. (1896) pp. 772-84, 815-25. 
f Zool. Anzeig., xix. (1896) pp. 266-8. 
t Proc. Roy. Irish Acad., iii. (1895) pp. 664-706 (2 pis.). 
