CHAP. VIII.] LIKENESSES IN ANIMALS AND PLANTS. 269 



the skull of the American gilled eft, Menobranchus, that, in 

 his opinion, &quot;No definite answer can be given &quot; to the ques 

 tion whether the trabeculse &quot; grow into adjacent tissues, as a 

 tree pushes its roots into the soil,&quot; or whether their apparent 

 extension does not &quot; arise rather from a chondrification of 

 the pre-existing tissue in the immediate neighbourhood of 

 the trabecular cartilage ?&quot; 



Secondly, when ossification begins to set in, the meaning 

 of the several ossific centres as they arise must be interpreted 

 by their later stages, or subsequent adult conditions in the 

 same animal or in other animals. How else could epiphyses 

 ever be discriminated from other ossific centres ? Airain, 



O &quot; 



the circumstance of a bone or cartilage making its appear 

 ance as a single element may in any case be due to the 

 junction of its incipiently distinct parts at a period anterior 

 to possible observation ; in other words, it may be made up 

 of parts which are called connate i.e., never distinct to 

 observation, though judged from analogy to be essentially 

 compound. Of such rationally inferred, but invisible, distinct 

 ness, botany offers us a multitude of examples. 



The stages passed through by the larvse of moths and 

 butterflies throw but a doubtful light on their adult con 

 dition ; and what misleading ideas might not be suggested 

 by the development of the Sitaris beetle? This insect, 

 instead of at first appearing in its grub stage, and then after 

 a time putting on the adult form, is at first active and fur 

 nished with six legs, two long antenna, and four eyes. 

 Hatched in the nests of bees, it at first attaches itself to one 

 of the males, and then crawls, when an opportunity offers, 

 upon a female bee. When the female bee lays her eggs, 

 the young Sitaris springs upon them and devours them. 

 Then, losing its eyes, legs, and ^antennae, it sinks into an 

 ordinary grub-like form, and feeds on honey, ultimately 

 undergoing another transformation, re-acquiring its legs and 

 antennae, and emerging a perfect beetle. 



Surely the results of development are as much to be con 

 sidered as are its earlier stages. I am far indeed from 



