ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
793 
size, and form of the hooks and teeth ; (5) the form of the olfactory 
organ ; and (6) the development of the generative organs. Three genera 
are recognized, Sagitta with eleven species, Krohnia with two, and 
Spadella with seven ; three species cannot be definitely assigned to a 
genus. Tables giving the distinctive characters of the species are 
appended, and there are, in conclusion, some observations on the dis- 
tribution of the forms that are found in the North Atlantic. 
The number of examples of Chaetognatha is so great that it would 
be one of the most interesting of biological questions to determine the 
part that they play in the economy of marine life. 
Helminthological Notes.* — Prof. M. Stossich has notes on numerous 
species of Trematoda, Cestoda, Nematoda, and Acanthocephala, chiefly 
in regard to their distribution in various hosts. He notes and figures 
some structural features of Echinorhynchus teres Westr., Tsenia serpentulus 
Schrank, T. Vallei Stossich, Ascaris ensicaudata Rud., A. scombrorum 
Stossich, Dispharagus aduncus Creplin, Heterakis monticelliana Stossich. 
Distomidae of Mammals. | — Prof. M. Stossich gives a list of sixty- 
one species, with their various hosts, and a corresponding list of eighty- 
three mammals with the Distomidae known to be parasitic in each. 
The whole matter is very clearly and tersely presented. 
Trematodes of Box salpa.J — Dr. F. S. Monticelli finds in Box 
salpa three Trematodes already known in this host and one new form. 
He gives a description of one of the known forms, Monostomum capi- 
tellatum Rud., and of the new species M. stossicManum , contrasting both 
in detail with M. spinosissimum Stossich. 
Life-history of Distoma hepaticum.§ — Dr. A. Lutz finds that the 
liver-fluke which has been seriously infesting cattle and horses in the 
Hawaian Islands passes its asexual life in a Lymnseus , which he had been 
led to regard as L. pereger, but which Leuckart in a note identifies (on 
O. Bottcher’s authority) as L. cahuensis Soul. Dr. Lutz notes that 
the Cercariae are only liberated from their host when it dies or when 
the shell is broken. He relates his experiments in infecting guinea- 
pigs and other small rodents. In a specie; of Melania he found in 
great abundance other rediae than those of the liver-fluke ; of these he 
promises an account. The author gives many interesting details in 
regard to Distoma hepaticum , which, apart from his discovery of a new 
host, are of interest, e. g. the great mortality among the infected snails, 
which are literally “eaten up of worms,” as many as 200 rediae 
occurring in one animal. 
Classification of Cestoda. || — M. A. Villot, in referring to the em- 
bryological researches of B. Grassi and G. Rovelli, maintains strongly 
the justice of his previous classification of cystic forms into Cysticerci, 
Cysticercoidei, and Pseudocystici. 
* Glasnik Hrv. Nar. Druztva (Soc. Hist. Nat. Croatica), vii. (1892) 10 pp 
(2 pis.). 
t ‘I Distomi nei Mammiferi. Lavoro monografico,’ 8vo, Trieste, 1892, pp. 42. 
X Atti R. Accad. Sci. Torino, xxvii. (1891-2) pp. 514-34 (1 pi.). 
§ Centralbl. f. Bakteriol. u. Parasitenk., xi. (1892) pp. 783-96 (1 fio-.). 
|| Zool. Anzeig., xv. (1892) pp. 210-12. 
1892. 3 H 
