164 Transactions. — Zoology. 



Female. (PI. XX., fig. 8.) In the article on " Crustacea," in Todd's 

 Cyclopaedia of Anatomy and Physiology, M. -Edwards says that there is a 

 striking analogy between the male and the female reproductive organs in 

 the Crustacea. This is certainly true as far as ParanepJirops setosus is con- 

 cerned, for the female reproductive organs are formed on the same plan as 

 the male. They differ very much in appearance, however, for the ovaries 

 (or) are much shorter and thicker than the testes. The two anterior por- 

 tions are but slightly separated at their anterior ends, and they approach to 

 one another and soon coalesce, so that there is no part which can properly 

 be called a commissure. Behind this they are at first widely separated, so 

 that a hollow is formed in which the heart rests. Posteriorly they rapidly 

 become narrower and approach closer to one another, so that they lie one 

 on each side of the intestine. From about the centre the two oviducts arise 

 and proceed without any convolutions direct to the openings on the basal 

 joints of the second pair of walking legs. 



I have not had an opportunity of observing how the young are 

 attached to the mother after birth, but according to Mr. Wood-Mason* 

 they fix themselves to the swimmerets of the mother by the hooked 

 ends of their hinder ambulatory legs, and not by the chelse as in 

 Astacas fluviatilis. 



DESCRIPTION OF PLATES XIX.— XXI. 

 Plate XIX. 

 In all the figures, ex, exopodite ; en, endopodite ; cxp, coxopodite ; bp, basipodite ; 

 ip, ischiopodite ; mp, meropodite ; cp, carpopodite; pp, propodite ; dp, dactylopodite. 

 Fig. 1. Antennule of left side (X 2). 



2. Antemia of left side (X 2) ; gg, opening of green gland. 



3. Mandibles of left side (x 2); p, palp. 



4. First maxilla of left side (X 2). 



5. Second maxilla of left side (x 2) ; sg, scaphognathite. 



6. First maxillipede of left side (X 2) ; ep, epipodite. 



7. Second maxillipede of left side (x 2) ; pb, podobranchia ; ab, arthrobranchia. 



8. Third or external maxillipede of left side (X 2); cxs, coxopoditic set® ; pb, 



podobranchia ; ab, arthrobranchia. 



9. Rostrum, side view (X 2). 



Plate XX. 

 Fig. 1. Third abdominal appendages of male (x 2); cxp, coxopodite; bp, basipodite; 

 ex, exopodite ; en, endopodite. 



2. Third abdominal appendages of female (x 2). Letters as in figure 1. 



3. The sixth abdominal appendage (x 2); cxp, coxopodite; ex, exopodite; en. 



endopodite. 



4. Telson(X*2). 



* Ann, and Mag. Nat. Hist., 4th series, vol. xviii. (1876), p. 306. 



