CRUSTACEA COPEPODA 



are three genera, Monstrilla, Haemocera, and Thaumaleus. The 

 best known type is Haemocera danae (often described as Monstrilla 

 danae). In the adult state (Fig. 30) there are no mouth-parts ; the 

 mouth is exceedingly small and leads into a very small stomach, 

 which ends blindly, while the whole body contains reserve food- 

 material in the form of brown oil-drops. The sole appendages on 



the head are the first an- 

 tennae ; but on the thorax 

 biramous feet are present by 

 means of which the animal 

 can swim with great rapidity. 

 This anomalous organisation 

 receives an explanation from 

 the remarkable development 

 through which the larva 

 passes. The larva is liberated 



77, 



Nd," 



FIG. 30. Haemocera, danae, x 40. A, Side FIG. 31. Free-swimming Nauplius 



view ? ; B, ventral view <J . Ant.l, 1st an- 

 tenna ; e, eye ; or, ovary ; ovd, oviduct '; St, 

 stomach ; Tk.l, 1st tlioracic appendage ; 

 Th.5, 5th thoracic segment ; vd, vas deferens. 

 (After Malaqnin.) 



larva of Haemocera danae ; Ant.l, 

 Ant.2, 1st and 2nd antennae ; e, 

 remains of eye ; Md, mandible. 

 (After Malaquin.) 



from the parent as a Nauplius with the structure shown in 

 .Fig. 31; it does not possess an alimentary canal. It makes 

 its way to a specimen of the Serpulid worm, Salmacina dysteri, 

 into the epidermis of which it penetrates by movements of the 

 antennae, hanging on all the time by means of the hooks on 

 the mandibles. From the epidermis it passes through the 

 muscles into the coelom of the worm, and thence into the 

 blood-vessels, usually coming to rest in the ventral blood- 



