90 Fort-Major T. Austin on the Genus Platycrinus. 



Annelides, &c. Upon organisms still so slightly differentiated 

 external conditions act in a very energetic manner ; and their 

 action is multiplied by heredity in creatures with a free 

 and dilated embryogeny. We must therefore keep watch 

 against the apparent homologies which often mask real 

 but yet only slightly marked differences of organization — 

 " When we have to do with the starting-point of an angle, 

 no modification in the divergence of the lines is indif- 

 ferent." 



Among those who will read the preceding pages there are 

 some who will regard such researches as rash, as useless 

 theories, or as facile dissertations ; so great is even still the 

 infatuation of certain naturalists for the exaggerations of the 

 Cuvierian school, and for the ideal and artistic morphology 

 of some of his successors. We have nothing to urge against 

 those who persist, in contempt of embryogenic data, in seeking 

 in adult forms for supposed, homologies of connexion and an 

 arbitrary plan determined beforehand. One cannot discuss 

 matters with a partisan. To those who pretend that it is 

 easy to reason upon known facts, and who prefer to seek and 

 store up in their memoirs histological details and observations 

 in descriptive anatomy, we say with Professor Hackel : — 

 " Whoever has good eyes and a microscope, assiduity, and 

 patience may now-a-days acquire a certain notoriety by micro- 

 scopical discoveries, but without therefore deserving the name 

 of a naturalist. This title must be reserved for the man who 

 endeavours not only to see the particular facts, but also to 

 grasp their ethological bond." 



IX. — Observations on the Genus Platycrinus. 

 By Fort-Major Thomas Austin, F.G.S. 



Having for a long time remarked the anomaly of retaining in 

 the genus Platycrinus those species which deviate from the 

 typical character in having the mouth, or anal orifice, or 

 whatever the office the aperture may have been intended to 

 perform, placed laterally or nearly so, whereas the typical 

 species and some others have the centre of the ventral dome 

 elevated into a tube from one to two inches in height, it is 

 therefore proposed to remove those species with excentrical 

 apertures into a new genus, retaining Platycrinus losvis and 

 all those with proboscicliform central tubes in the original 

 genus. 



