66 TRANSACTIONS LIYEEPOOL BIOLOGICAL SOCIETY. 



13. MacrorhyjwJiusnaegelii, Kollikei. (PL XIII, fig. 21.) 

 In form, colour and size this species closely resembles 



the foregoing. It may be readily distinguished, however, 

 by the presence of a special chitinous investment round 

 the lower portion of the granule- vesicle. This is a short 

 funnel-shaped tube, the wide mouth of which is usually 

 provided with a curved spur. 



The great bulk of the genital organs in this and other 

 species of Proboscidse, leads, during the development of 

 the individual, to the loss of the alimentary canal as a 

 definite coherent structure. Consequently, examination 

 of adults shews that the body is almost exclusively filled 

 with the reproductive apparatus, the gut being merely 

 represented by isolated cells. 



This species occurs at Port Erin, Millport, and 

 Plymouth. 



14. Macrorhynchus helgolandicus, Met. (PI. XIII, fig. 22.) 

 During my visit to the Port Erin Station, during October 



of last year I found a number of immature examples of 

 this form which is distinguished from all other species of 

 Macrorhynchus by the possession of a special "poison- 

 dart " in addition to complicated male and female 

 copulatory organs. This had led v. Graff to place this 

 species in a special division " Venenosi " as opposed the 

 remaining Macrorhjmchus-species included as " Typici." 

 M. lielgolaiidicus has also occurred at Millport and 

 Plymouth. 



15. Hyporh/ynclius armafus, Jens. (PI. XIII, figs. 23, 24.) 

 Length 1 mm. Body very elongate, thread-like and 



of a white colour. Although usually associated with 

 other Turbellaria of a similar colour and appearance, this 

 species is distinguished (as they are m turn) by peculiarities 

 of locomotion which are sufiicient to enable one to 

 identify it even with the naked eye. The proboscis (as in 



