MICROSCOPICAL STUDIES. 47 



(ratio 11 to 8) ; the hinge between the 4th and terminal joints of 

 his antennas is absent in those of the female ; he is without the 

 rudimentary fifth pair of swimming feet present in the female, and 

 the sexual orifices which open in both sexes on the under side of the 

 1st abdominal segment, are in the male situated on stout low 

 prominences (Fig. 10, /.) ; in the female when mature, these are 

 produced into long tubes reaching backwards considerably beyond the 

 ends of the caudal bristles. Internally both ovaries and testes lie as 

 two great paired glands in the cephalothorax. Both sexes have in 

 this species two distinct efferent ducts whereby the genital products 

 are passed downwards and obtain egress at the openings already 

 mentioned. The function of the long tubular genital processes of 

 the female (c) is probably to give attachment to the ova after 

 being extruded, as Mr. I. C. Thompson has observed ova adherent 

 to them in an allied species (4). 



References : — 



1. Lubbock, Sir John. — Ann. & Mag. Nat. Hist, Vol. xx, 2nd 



Series, 1857. 



2. Brady, Prof. G. S. — A Monograph of Br. Copepoda (Ray 



Soc), Vol. iii, 1880. 



3. Thompson, I. C. — Second Rep. on Copepoda of L'pool Bay 



(Trans. Biol. Soc. L'pool, Vol. II), 1887. 



4. " " — Copepoda of Madeira (Journ. Linn. Soc. 



Zool, Vol. xx), 1887. 



5. " " — Monstrilla & the Cymbasomatidce (Trans- 



Biol. Soc. L'pool, Vol. iv), 1890. 



6. — Revised Rpp. on Copepoda of L'pool Bay 



(Trans. Biol. Soc. L'pool, Vol. vii), 1893. 



7. Bourne, G. C. — Notes on the Genus Monstrilla (Quart. 



Journ. of Micro. Sc), Feb. 1890. 



Explanation of Plate IV, Figs. 9 — 12. 

 Monstrilla anglica (Lubbock). 



Fig. 9. Side view of a female full of ova (size 3 mm.), am antennary 

 muscles, e eye, o proboscis, c genital tubes. (Note — No 

 definite articulation should be shown between the fourth 

 and terminal joints of the antennae. Such is shown 

 here by a slip in drawing. 



Fig. 10 & 11. Lateral and dorsal view of a male (size 225 mm.), 

 a branched sensory hairs, b straight tactile (?) hairs, 

 m 1 & m [i , the extensors muscles of the segment next 

 behind the carapace, m™ & m iv flexor muscles of same, 

 1, 2, 3 & 4 abdominal segments, / genital prominence, 

 d the 6th or slight seta of the caudal fork. 



Fig. 12. View from behind, of the third pair of swimming feet. 



