Article V. — Xnfes on Species of North American O/if/oclnpfa. V. 

 The Si/sfeni(ffic Re/nfionships of Luinhricidits (Thinodrihis ) 

 ine(in^t(fii>< I Smith). By Frank Smith. 



Wheu this species was described by the writer (ls95) it 

 was thought that the differences between it and previously 

 described species were such as to warrant the recognition of a 

 new genus: hence the genus Thinodrihix. Michaelsen in his 

 great work on the Oh'(/()rh<rfa ( 1900) saw ht to include thisspecies 

 in the genus Trivhuilrilus Clapar^de with the two European 

 species. Kecent papers on the reproductive organs of Linnhrlr- 

 i(/i<^ rariei/dfiis ^Miiller) by Weuig O^O'Jl and Hesse (1902) 

 have extended our knowledge of that species and have shown 

 that it is in some particulars very similar to ThiiiddriJus in- 

 coiisfdiis. and as it now seems to the writer that there is more rea- 

 son for including the latter species in the genus Liniiliricii/ii.f 

 than in the genus TriehotlrilKs. it will l)e referred to in the fol- 

 lowing discussion as Linnhricnhis inconsfans. 



We will first consider the chief points in which L. iticonsfans 

 differs more from L. rririe(/af its than from the two species of Tri- 

 (■hi)(/rihfs {T. '//A;/*/')//'"" L'laparede and 7'. /<r^^//f'>^s7'.s' Vejdovsky). 



AlliKincn (iliinil. — An albumen or coimlatory gland, which 

 is described and hgured l)y Vejdovsky (1884) as occurring in 

 somite IX in L. niricipdns. is lacking in Trichodriliis and in L. 

 incon.sfans. No reference is made to such an organ by Wenig 

 and Hesse in their recent papers on L. rarici/dfus. and ^lichael- 

 sen (1908, p. 60) has recently raised the question as to its oc- 

 currence, and queries whether the structures seen by \'ejdov- 

 sky may not have been rudiments of efferent reproductive 

 organs. It should not be overlooked that the structure of the 

 albumen gland is described by Vejdovsky (1884, p. 149) as simi- 

 lar to that of the si)ermathec;e, and that Wenig (1902) de- 

 scribes and figures a single spermatheca in IX but makes no 

 reference to an albumen gland. N'ejdovsky used the presence 



