REPORT ON THE OPHIUROIDEA. 



NOTE ON FOSSIL SPECIES. 



In 1869 Liitken published a short but satisfactory critique on the then known fossil 

 Ophiurans.^ He mentions nearly fifty sj^ecies, and his general conclusion is that they 

 have no certain standing, either genericaUy or specifically. The latest resumd ^ shows 

 that no real progi'ess in the definition of these fossils has been made during the past 

 twelve years. For this there are two reasons, (1) that many of the type specimens are 

 ill preserved, and especially deficient in the mouth parts ; (2) tliat nobody who knew 

 much of the subject has made a general examination of the originals. Here is an ex- 

 cellent field for a palseontologist. It cannot be doubted that the museums have a great 

 many unstudied species. Indeed I have myself seen some in the European collections. 

 When we consider the variety of living Ophiurans, and their occurrence in every climate 

 and at every depth, it is plain that he would throw much light on palaeontology who 

 would bring together and thoroughly study their fossil forms. At present it cannot be 

 said that a single fossil genus is identical with the living. The most probable identity 

 is that of the Oolitic Ophioderma (OjMitra) egertoni,^ which may well be an OjMura, 

 an Ophiopeza, or a Pectinura; most probably the last. Another fossil long known 

 is the Triassic Aspidura loricata,^ which certainly has a considerable likeness to 

 Opldomastus (PL VIII. figs. 16-18), especially on the under side. Goldfuss has correctly 

 drawn the little primary plates in the centre of the back as in the brachial spaces ; 

 and I suspect Polig is wrong in putting them in the interbrachial, where they are 

 never found among the living. I agree, too, with Ludwig that the supposed division 

 in halves of the mouth shields is highly improbable. Another Triassic form, Aspidura 

 ludeni,^ has nearly the whole arm occupied by swollen side arm plates, and may possibly 

 stand near such a species as OpMomusium eburneum. Op)Molep)is damesii from the OoHte 

 has similar side arm plates ; ^ and so has the Oolitic Ophiolepis leclcenhyi,^ with the ad- 

 ditional peculiarity of a microscopic surface tuberculation like that of Ophioglypha 

 convexa and some other deep-sea species (PL VI. figs. 13-15). The same large, swollen, 

 tuberculated side arm plates are found in Ophiocoma granidosa^ from the Chalk. On 

 the whole, it may be said that from the Trias ujiward there is nothing very unfamiliar 

 in the look of the Ophiurans, although to find some of the shapes, we must go into 



1 Aildit. ad Hist. Oph., vol. iii. p. 70, 1869. 



2 Zittel, Handbiicli der PalKontologie, vol. i. p. 4.39, 1880. 



3 Briidc-rip, Trans. Geol. Soc, 2ud Ser., pi. xii. fig. G. 



^ Goldfuss, Petrel'acta Gemiaiiijp, pi. xlii. fig. 7 ; Pulig. Zeitschrift f. Wissensch., Zoologie, vol. xxxi. p. 235, 

 pi. xvii. figs. 10-14 ; Liuhvig, Zool., Anzeiger, Jan. 1879, p. 41. 

 '" Hagenow, Pal<eontographica, vol. i. p. 21, pil. i. fig. 1. 

 •s AV right, Monog. British Fossil Echinoderni, vol. ii., pi. xxi. figs. 4, b. 



7 Wright, loc. cit, pi. xix. fig. 3. 



8 Roemer, Versteinermigen des Norddeutsclien Kreidegcbirges, 1841, jj. vi. fig. 22. 



