604 
ZOOLOGICAL LITERATURE. 
the families and other groups under which the species fall, 
together with ample bibliographical citations, are interspersed. 
The Hirudmea of the Brest coast are, in many cases, bril- 
liantly coloured, and in this marked respect contrast with the 
more sombre species of the German ocean. This holds good 
when we compare different species of the same genus, or even 
different individuals of the same species. 
Van Beneden divides the Bdellodes {Hirudmea) into three 
principal groups, including eight families, as follows ; — 
BDELLODA— 
ScLEROBDELLAiREA : Gnatobdellina, Ichtliyobdellina, Glossobdellina, 
Brancbiobdellina, Heterobdellina. 
IIiSTRioBDELLAiREA *. Astacobdellina, Histriobdellina. 
Malacobdellairea : Malacobdellina. 
According to our authors, there is this correlation between 
certain Hirudmea and their hosts — that those most complex in 
structure are found on the most highly organized animals. Thus 
Gnatobdellina infest mammals, PontohdeUce fishes, Histriohdellce 
crustaceans, and Malacobdelhe mollusks. 
Remarks on known species and genera \ — 
Van Beneden and Hesse notice the following species: — 
PontobdeUa muricata j Ichthyohdella anarrhiccB ; I. hippoglossi ; Histrio- 
hdella homariy Malacohdella grossa. (All figured, except Histnobdella homari). 
New genera and species ; — 
Van Beneden and Hesse describe thirteen new species, inclu- 
ding five new genera. All the species are figured, with various 
anatomical details, 
Fam. ICHTHYOBDELLIDiE. 
Dactylobdelluy n. g. Characters of PontobdeUa, except that the head is 
crowned with a double series of digitiform prolongations, which probably 
contribute to aid respiration. Sp. D. musteli. 
OphibdeUa, n. g. Cephalic sucker large, hood-shaped j digestive canal 
furnished with a proboscis j cutaneous folds smooth, distinct. Sp. O. labracis. 
Ichthyobdella rhombi I. lusece. 
Fam. Branchiobdellid^. 
Branchellio rhombi. 
Calliobdella, n. g. A sucker at each end of the body, the hinder one very 
large and simple ; body divided into two regions, an oral and a postnuchal, 
the cutaneous rings of the latter supporting tubercles on either side. Sp. 
C. lophii 5 C, punctata ; C. striata. 
IlemibdeUa, n. g. Body cylindrical, with an anterior constriction as in the 
last genus ; oral sucker small, distinct ; anal sucker less so, with wrinkled 
margin, capable of contracting itself so as to act the part of a prehensile 
