12 Fishery Board for Scotland. 



Thei"e are three principal lateral denticulations to the carapace, the outer 

 angle of the orbit being regarded as one of the series. Two smaller teeth 

 occupy positions between the principal teeth. In the adult the five 

 denticulations are equal in size. 



The hooks which were present in the Megnlops on the coxopodites of the 

 second, thirdj and fourth pereiopods and on the ischiopodite of the chela are 

 absent. There is a big angle tooth on the carpopodite of the chela (fig. 29). 



There appear to be minute needle-point cilia on the carapace, but this 

 was not satisfactorily determined. 



In the cast integument (Megalops) from which came the first young 

 stage I was unable to make out the presence of a dorsal spine. The region 

 from which it rises was crumpled. The long rostral spine was present. 



The abdomen of the first young stage is closely applied to the thorax ; 

 the pleopods are still large, but are without setae. 



POKTUNUS DBPURATOR. 



The I. Zoese of this species have been kindly supplied to me by Mr. H. 

 T. Waddington, Bournemouth. 



The eggs hatched under observation. '^Five days after the crab had 

 got rid of its eggs it extruded a new batch. These proceeded to develop 

 regularly." 



/. Zoea, figs. 31, 84; Abdomen, figs. 41, 44; Telson, fig. 39. 



After being preserved in formaline this Zoea resembled much the pre- 

 served Zoese of holsatus and puber in pigmentation. In structure also this 

 Zoea is very similar to those of holsatus and puber. 



The lateral spines of the carapace are long and slender. 



No hairs were made out on the free edge of the carapace. The 

 " branchiostegal tooth " is present. 



The abdomen is shown in side view in fig. 41. The studs are present on 

 the second and third segments. The lateral hind edge of the second, third, 

 fourth, and fifth segments is slightly serrated. The ventral tooth (sp.) is 

 evidently the principal one. The serrations may be detected in front view, 

 fig. 44. A pair of hairs is present on the posterior dorsal edge of the 

 second, third, fourth, and fifth segments. 



On the telson (fig. 39) the teeth on the outside of the prong are 

 prominent. The proximal tooth is very large. The middle tooth is 

 markedly curved, and ends in a fine apex. 



I have not had the opportunity of examining any later stages of this 

 species. 



Comparison betiveen the Zoece of Portimzis holsatus, puber, and depurator. 



I. Zoea. — The Zoese of holsatus and puber which have been preserved in 

 formaline show a very difi"erent naked-eye appeai-ance. The body of puber 

 is white, or nearly colourless, with the brown eyes prominent. The larvae 

 of holsatus show a good deal of dark brown pigment in the body and eyes. 



The lateral spines of the carapace seem to be longer in holsatus and 

 depurator than in the puber. In the abdomen, puber (fig. 45) shows 

 the most prominently serrated edges to the second, third, fourth, and fifth 

 segments : cp. holsatus, fig. 15 ; depurator, fig. 41. Little difference is 

 made out in the telson, except that in depurator (fig. 39) the proximal 

 tooth in the prong is very large, being much lai'ger than the two other 

 teeth. In holsatus (fig. 18) the proximal tooth is the largest, but it is a 

 smaller tooth than that of depurator. In puber (fig. 47) the proximal tooth 

 was not larger than the distal. 



